Page 6 - Industrial Technology EXTRA 24th May 2021

from manual to electrohydraulic
actuation, as well designers looking to
reduce the size of main system circuits
on mini and micro platforms.
The market demand is
clear to see. Effective
flow sharing is
paramount on machines
such as mini excavators,
where up to three or four
operations often take place
simultaneously. This workload makes it easy
for flow saturation to occur every time the
operator calls for more oil flow than the pump can
deliver. Put simply, flow-sharing capability helps to
Compared with cast-iron alternatives, the guarantee movement.
development of a valve with aluminium sections In addition to flow sharing, load sense is another
would certainly serve to cut overall weight, thus requirement for this type of solution. Load sensing
benefiting fuel efficiency, particularly if there was is when the load-induced pressure downstream of
also a reduction in the dimensional envelope. an orifice is ‘sensed’ and pump flow adjusted to
Furthermore, offering screw-in capability would maintain a constant pressure drop (and thus flow)
deliver versatility, agility and serviceability for end across the orifice. This 'orifice' is usually a
users and maintenance technicians. directional control valve with proportional flow
Having access to a valve of this capability and characteristics. The benefits of load sensing are far-
performance would render it ideal for mini and reaching, and include the ability to adapt the
micro machinery platforms across a variety of machine to any load condition, the potential to
industry applications, not least construction provide full performance at variable load cycles, and
vehicles like excavators, wheel loaders, skid steer the predictability of machine stability and system
loaders and trenchers, as well as tractors and function.
various attachments used in the agriculture sector.
Of course, there are many material handling Design innovation
systems that could also benefit from excellent low- Designing and developing a flow-sharing, load-
flow control, including spider cranes, truck-mounted sensing valve that offers greater functionality in a
cranes, aerial work platforms, lift trucks and smaller package requires expertise, both in the
telehandlers. Further applications might include actual technology and its potential applications.
snow and ice management vehicles, road sweepers So, what form might a solution of this kind take?
and lawnmowers, not forgetting auxiliary/accessory One option is a proportional (four-way, three-
control on larger machines. position) solenoid cartridge valve based on a
In short, developing a valve able to help sectional concept, where multiple sections could be
optimise the performance of these machines would stacked to provide stable control. These sections
bring notable advantages to any OEM upgrading would have to be smaller than the cast-iron slices of

May 2021 • INDUSTRIAL TECHNOLOGY EXTRA • p6